PING: RFR: 8185796: jstack and clhsdb jstack should show lock objects

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PING: RFR: 8185796: jstack and clhsdb jstack should show lock objects

Yasumasa Suenaga-4
PING:
Could you review it? We need a reviewer and sponsor.

>>>    http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/


Thanks,

Yasumasa


2017-11-09 23:34 GMT+09:00 Yasumasa Suenaga <[hidden email]>:

> Thanks, Jini!
>
> I'm waiting for Reviewer and sponsor.
>
>
> Yasumasa
>
>
>
> On 2017/11/09 23:25, Jini George wrote:
>>
>> Hi Yasumasa,
>>
>> This looks fine to me.
>>
>> Thank you,
>> Jini (Not a Reviewer).
>>
>> On 11/9/2017 6:55 PM, Yasumasa Suenaga wrote:
>>>
>>> Hi Jini,
>>>
>>> Thank you for your comment!
>>> I've fixed and uploaded new webrev:
>>>
>>>    http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/
>>>
>>>> *
>>>>
>>>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/JavaVFrame.java
>>>>
>>>> -> Lines 198-212: I feel this commented out code could be removed and
>>>> replaced by a call to printLockInfo(), though I am not entirely sure as
>>>> to when this printOn() gets exercised.
>>>
>>>
>>> I agree with you to remove these comments.
>>> They are insufficient to show all locks like a my first webrev [1].
>>> webrev.04 is implemented to follow HotSpot implementation.
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>>
>>>
>>> [1] http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.00/
>>>
>>>
>>>
>>> On 2017/11/09 2:19, Jini George wrote:
>>>>
>>>> Hi Yasumasa,
>>>>
>>>> Your changes look good to me overall. Some nits:
>>>>
>>>> *
>>>>
>>>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/BasicType.java
>>>> (lines 138 to 152):
>>>> -> It would be nice if you could indent the "case" statements.
>>>>
>>>> *
>>>>
>>>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/ui/classbrowser/HTMLGenerator.java
>>>> -> It would be good if the indentation here for the newly added lines
>>>> matches that of the rest of the file. (4 spaces instead of 2).
>>>>
>>>> *
>>>>
>>>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/JavaVFrame.java
>>>>
>>>> -> Lines 198-212: I feel this commented out code could be removed and
>>>> replaced by a call to printLockInfo(), though I am not entirely sure as
>>>> to when this printOn() gets exercised.
>>>>
>>>> * test/hotspot/jtreg/serviceability/sa/TestJhsdbJstackLock.java
>>>> -> You can remove these lines:
>>>> import java.util.Scanner;
>>>> import java.util.stream.Collectors;
>>>> import java.io.File;
>>>>
>>>> Thanks,
>>>> Jini (Not a Reviewer).
>>>>
>>>>
>>>> On 11/1/2017 6:28 PM, Yasumasa Suenaga wrote:
>>>>>
>>>>> PING: Could you review and sponsor it?
>>>>>
>>>>>> ?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.03/
>>>>>
>>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Yasumasa
>>>>>
>>>>>
>>>>> On 2017/10/09 23:19, Yasumasa Suenaga wrote:
>>>>>>
>>>>>> Hi all,
>>>>>>
>>>>>> I uploaded new webrev to be adapted to current jdk10/hs:
>>>>>>
>>>>>> ?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.03/
>>>>>>
>>>>>>
>>>>>> Please review and sponsor it.
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Yasumasa
>>>>>>
>>>>>>
>>>>>> On 2017/09/27 0:31, Yasumasa Suenaga wrote:
>>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> I uploaded new webrev to be adapted to jdk10/hs:
>>>>>>>
>>>>>>> ?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.02/
>>>>>>>
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>> Yasumasa
>>>>>>>
>>>>>>>
>>>>>>> On 2017/08/24 22:59, Yasumasa Suenaga wrote:
>>>>>>>>
>>>>>>>> Thanks Jini!
>>>>>>>>
>>>>>>>> I uploaded new webrev:
>>>>>>>>
>>>>>>>> ?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.01/
>>>>>>>>
>>>>>>>> This webrev has been ported print_lock_info() to JavaVFrame.java,
>>>>>>>> and I've added new testcase for `jhsdb jstack` and jstack command on
>>>>>>>> `jhsdb clhsdb`.
>>>>>>>>
>>>>>>>>
>>>>>>>> Yasumasa
>>>>>>>>
>>>>>>>>
>>>>>>>> On 2017/08/24 18:01, Jini George wrote:
>>>>>>>>>
>>>>>>>>> Apologize for the late reply, Yasumasa.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> I think so, but I guess it is difficult.
>>>>>>>>>> For example, test for CLHSDB command is provided as
>>>>>>>>>> test/serviceability/sa/TestPrintMdo.java .
>>>>>>>>>> But target process seems to be fixed to "LingeredApp".
>>>>>>>>>> Can we change it to another program which generates lock
>>>>>>>>>> contention?
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> You can take a look at any of the
>>>>>>>>> hotspot/test/serviceability/sa/LingeredAppWith*.java files for
>>>>>>>>> this. The target process does not have to be be fixed to
>>>>>>>>> LingeredApp -- in these LingeredAppWith* cases, the targets are
>>>>>>>>> test-specific variations built on top of LingeredApp for ease of
>>>>>>>>> implementation.
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Jini.
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Re: PING: RFR: 8185796: jstack and clhsdb jstack should show lock objects

Yasumasa Suenaga-4
PING:

Could you review it?

>>>>     http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/

I want to merge this change to jdk 10. So I need a reviewer and sponsor.


Yasumasa


On 2017/11/14 9:58, Yasumasa Suenaga wrote:

> PING:
> Could you review it? We need a reviewer and sponsor.
>
>>>>     http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/
>
>
> Thanks,
>
> Yasumasa
>
>
> 2017-11-09 23:34 GMT+09:00 Yasumasa Suenaga <[hidden email]>:
>> Thanks, Jini!
>>
>> I'm waiting for Reviewer and sponsor.
>>
>>
>> Yasumasa
>>
>>
>>
>> On 2017/11/09 23:25, Jini George wrote:
>>>
>>> Hi Yasumasa,
>>>
>>> This looks fine to me.
>>>
>>> Thank you,
>>> Jini (Not a Reviewer).
>>>
>>> On 11/9/2017 6:55 PM, Yasumasa Suenaga wrote:
>>>>
>>>> Hi Jini,
>>>>
>>>> Thank you for your comment!
>>>> I've fixed and uploaded new webrev:
>>>>
>>>>     http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/
>>>>
>>>>> *
>>>>>
>>>>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/JavaVFrame.java
>>>>>
>>>>> -> Lines 198-212: I feel this commented out code could be removed and
>>>>> replaced by a call to printLockInfo(), though I am not entirely sure as
>>>>> to when this printOn() gets exercised.
>>>>
>>>>
>>>> I agree with you to remove these comments.
>>>> They are insufficient to show all locks like a my first webrev [1].
>>>> webrev.04 is implemented to follow HotSpot implementation.
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Yasumasa
>>>>
>>>>
>>>> [1] http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.00/
>>>>
>>>>
>>>>
>>>> On 2017/11/09 2:19, Jini George wrote:
>>>>>
>>>>> Hi Yasumasa,
>>>>>
>>>>> Your changes look good to me overall. Some nits:
>>>>>
>>>>> *
>>>>>
>>>>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/BasicType.java
>>>>> (lines 138 to 152):
>>>>> -> It would be nice if you could indent the "case" statements.
>>>>>
>>>>> *
>>>>>
>>>>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/ui/classbrowser/HTMLGenerator.java
>>>>> -> It would be good if the indentation here for the newly added lines
>>>>> matches that of the rest of the file. (4 spaces instead of 2).
>>>>>
>>>>> *
>>>>>
>>>>> src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/JavaVFrame.java
>>>>>
>>>>> -> Lines 198-212: I feel this commented out code could be removed and
>>>>> replaced by a call to printLockInfo(), though I am not entirely sure as
>>>>> to when this printOn() gets exercised.
>>>>>
>>>>> * test/hotspot/jtreg/serviceability/sa/TestJhsdbJstackLock.java
>>>>> -> You can remove these lines:
>>>>> import java.util.Scanner;
>>>>> import java.util.stream.Collectors;
>>>>> import java.io.File;
>>>>>
>>>>> Thanks,
>>>>> Jini (Not a Reviewer).
>>>>>
>>>>>
>>>>> On 11/1/2017 6:28 PM, Yasumasa Suenaga wrote:
>>>>>>
>>>>>> PING: Could you review and sponsor it?
>>>>>>
>>>>>>> ?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.03/
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Yasumasa
>>>>>>
>>>>>>
>>>>>> On 2017/10/09 23:19, Yasumasa Suenaga wrote:
>>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> I uploaded new webrev to be adapted to current jdk10/hs:
>>>>>>>
>>>>>>> ?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.03/
>>>>>>>
>>>>>>>
>>>>>>> Please review and sponsor it.
>>>>>>>
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>> Yasumasa
>>>>>>>
>>>>>>>
>>>>>>> On 2017/09/27 0:31, Yasumasa Suenaga wrote:
>>>>>>>>
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> I uploaded new webrev to be adapted to jdk10/hs:
>>>>>>>>
>>>>>>>> ?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.02/
>>>>>>>>
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>>
>>>>>>>> Yasumasa
>>>>>>>>
>>>>>>>>
>>>>>>>> On 2017/08/24 22:59, Yasumasa Suenaga wrote:
>>>>>>>>>
>>>>>>>>> Thanks Jini!
>>>>>>>>>
>>>>>>>>> I uploaded new webrev:
>>>>>>>>>
>>>>>>>>> ?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.01/
>>>>>>>>>
>>>>>>>>> This webrev has been ported print_lock_info() to JavaVFrame.java,
>>>>>>>>> and I've added new testcase for `jhsdb jstack` and jstack command on
>>>>>>>>> `jhsdb clhsdb`.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Yasumasa
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On 2017/08/24 18:01, Jini George wrote:
>>>>>>>>>>
>>>>>>>>>> Apologize for the late reply, Yasumasa.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>> I think so, but I guess it is difficult.
>>>>>>>>>>> For example, test for CLHSDB command is provided as
>>>>>>>>>>> test/serviceability/sa/TestPrintMdo.java .
>>>>>>>>>>> But target process seems to be fixed to "LingeredApp".
>>>>>>>>>>> Can we change it to another program which generates lock
>>>>>>>>>>> contention?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> You can take a look at any of the
>>>>>>>>>> hotspot/test/serviceability/sa/LingeredAppWith*.java files for
>>>>>>>>>> this. The target process does not have to be be fixed to
>>>>>>>>>> LingeredApp -- in these LingeredAppWith* cases, the targets are
>>>>>>>>>> test-specific variations built on top of LingeredApp for ease of
>>>>>>>>>> implementation.
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>> Jini.
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Re: PING: RFR: 8185796: jstack and clhsdb jstack should show lock objects

serguei.spitsyn@oracle.com
Hi Yasumasa,

http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/oops/java_lang_Class.java.udiff.html

+  public static String asExternalName(Oop aClass) {
+    Klass k = java_lang_Class.asKlass(aClass);
+    if (k == null) { // primitive
+      BasicType type = BasicType.T_VOID;
+      ArrayKlass ak = (ArrayKlass)Metadata.instantiateWrapperFor(
+                             aClass.getHandle().getAddressAt(arrayKlassOffset));
+      if (ak != null) {
+        type = BasicType.intToBasicType(ak.getElementType());
+      }
If I understand correctly, it is array of a primitive type, not a primitive.
The comment needs to be updated accordingly.


http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/BasicType.java.udiff.html

It looks like the change is a little bit more complex than necessary.
It could be enough to just introduce new method getName() like this:
public String getName() {
  String name = "ILLEGAL TYPE";
  switch (type) {
    case tBoolean: name = "boolean";
    . . .
  }
  return name;
}

http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/JavaVFrame.java.udiff.html

The logic in the printLockInfo() is unclear because there are two almost identical fragments here:
+        if (monitor.owner() != null) {
+          // the monitor is associated with an object, i.e., it is locked
+
+          Mark mark = null;
+          String lockState = "locked";
+          if (!foundFirstMonitor && frameCount == 0) {
+            // If this is the first frame and we haven't found an owned
+            // monitor before, then we need to see if we have completed
+            // the lock or if we are blocked trying to acquire it. Only
+            // an inflated monitor that is first on the monitor list in
+            // the first frame can block us on a monitor enter.
+            mark = new Mark(monitor.owner());
+            if (mark.hasMonitor() &&
+                ( // we have marked ourself as pending on this monitor
+                  mark.monitor().equals(thread.getCurrentPendingMonitor()) ||
+                  // we are not the owner of this monitor
+                  !mark.monitor().isEntered(thread)
+                )) {
+              lockState = "waiting to lock";
+            } else {
+              // We own the monitor which is not as interesting so
+              // disable the extra printing below.
+              mark = null;
+            }
+          } else if (frameCount != 0) {
+            // This is not the first frame so we either own this monitor
+            // or we owned the monitor before and called wait(). Because
+            // wait() could have been called on any monitor in a lower
+            // numbered frame on the stack, we have to check all the
+            // monitors on the list for this frame.
+            mark = new Mark(monitor.owner());
+            if (mark.hasMonitor() &&
+                ( // we have marked ourself as pending on this monitor
+                  mark.monitor().equals(thread.getCurrentPendingMonitor()) ||
+                  // we are not the owner of this monitor
+                  !mark.monitor().isEntered(thread)
+                )) {
+              lockState = "waiting to re-lock in wait()";
+            } else {
+              // We own the monitor which is not as interesting so
+              // disable the extra printing below.
+              mark = null;
+            }
+          }
+          printLockedObjectClassName(tty, monitor.owner(), lockState);
+          foundFirstMonitor = true;


A way to simplify this part would be to add a method like this:

  String identifyLockState(String waitingState) {
    Mark mark = new Mark(monitor.owner());
    String lockState = "locked";
    if (mark.hasMonitor() &&
        ( // we have marked ourself as pending on this monitor
          mark.monitor().equals(thread.getCurrentPendingMonitor()) ||
          // we are not the owner of this monitor
          !mark.monitor().isEntered(thread)
        )) {
      lockState = waitingState;
    }
    return lockState;
  }


Then the fragment above could be reduced to:

    if (monitor.owner() != null) {
      // the monitor is associated with an object, i.e., it is locked
      String lockState = "locked";
      if (!foundFirstMonitor && frameCount == 0) {
        lockState = identifyLockState("waiting to lock");
      } else if (frameCount != 0) {
        lockState = identifyLockState("waiting to re-lock in wait()");
      }
      printLockedObjectClassName(tty, monitor.owner(), lockState);
      foundFirstMonitor = true;
    }


http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/test/hotspot/jtreg/serviceability/sa/LingeredAppWithLock.java.html

The indent is inconsistent, the lines 29-37 have 2 instead of 4.
  30       synchronized(lock) {
  Space is missed before '('.

  40         Thread classLock1 = new Thread(
  41                                    () -> lockMethod(LingeredAppWithLock.class));
  42         Thread classLock2 = new Thread(
  43                                    () -> lockMethod(LingeredAppWithLock.class));
  44         Thread objectLock = new Thread(() -> lockMethod(classLock1));
  45         Thread primitiveLock = new Thread(() -> lockMethod(int.class));
  No need to separate lines at 40-43.


http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/test/hotspot/jtreg/serviceability/sa/TestClhsdbJstackLock.java.html

Indent 3 instead of 4 in the fragment 97-101.

No need to to split the lines:
 114         System.out.println(
 115             pb.command().stream().collect(Collectors.joining(" ")));
 . . .
 156             System.out.println(
 157                "SA attach not expected to work - test skipped.");


http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/test/hotspot/jtreg/serviceability/sa/TestJhsdbJstackLock.java.html
  49             System.out.println(
  50                "SA attach not expected to work - test skipped.");
  No need to split the line above.




On 11/19/17 05:37, Yasumasa Suenaga wrote:
PING:

Could you review it?

    http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/

I want to merge this change to jdk 10. So I need a reviewer and sponsor.


Jini, could you, take care about this sponsorship?


Thanks,
Serguei


Yasumasa


On 2017/11/14 9:58, Yasumasa Suenaga wrote:
PING:
Could you review it? We need a reviewer and sponsor.

    http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/


Thanks,

Yasumasa


2017-11-09 23:34 GMT+09:00 Yasumasa Suenaga [hidden email]:
Thanks, Jini!

I'm waiting for Reviewer and sponsor.


Yasumasa



On 2017/11/09 23:25, Jini George wrote:

Hi Yasumasa,

This looks fine to me.

Thank you,
Jini (Not a Reviewer).

On 11/9/2017 6:55 PM, Yasumasa Suenaga wrote:

Hi Jini,

Thank you for your comment!
I've fixed and uploaded new webrev:

    http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.04/

*

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/JavaVFrame.java

-> Lines 198-212: I feel this commented out code could be removed and
replaced by a call to printLockInfo(), though I am not entirely sure as
to when this printOn() gets exercised.


I agree with you to remove these comments.
They are insufficient to show all locks like a my first webrev [1].
webrev.04 is implemented to follow HotSpot implementation.


Thanks,

Yasumasa


[1] http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.00/



On 2017/11/09 2:19, Jini George wrote:

Hi Yasumasa,

Your changes look good to me overall. Some nits:

*

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/BasicType.java
(lines 138 to 152):
-> It would be nice if you could indent the "case" statements.

*

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/ui/classbrowser/HTMLGenerator.java
-> It would be good if the indentation here for the newly added lines
matches that of the rest of the file. (4 spaces instead of 2).

*

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/JavaVFrame.java

-> Lines 198-212: I feel this commented out code could be removed and
replaced by a call to printLockInfo(), though I am not entirely sure as
to when this printOn() gets exercised.

* test/hotspot/jtreg/serviceability/sa/TestJhsdbJstackLock.java
-> You can remove these lines:
import java.util.Scanner;
import java.util.stream.Collectors;
import java.io.File;

Thanks,
Jini (Not a Reviewer).


On 11/1/2017 6:28 PM, Yasumasa Suenaga wrote:

PING: Could you review and sponsor it?

?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.03/



Thanks,

Yasumasa


On 2017/10/09 23:19, Yasumasa Suenaga wrote:

Hi all,

I uploaded new webrev to be adapted to current jdk10/hs:

?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.03/


Please review and sponsor it.


Thanks,

Yasumasa


On 2017/09/27 0:31, Yasumasa Suenaga wrote:

Hi all,

I uploaded new webrev to be adapted to jdk10/hs:

?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.02/


Thanks,

Yasumasa


On 2017/08/24 22:59, Yasumasa Suenaga wrote:

Thanks Jini!

I uploaded new webrev:

?? http://cr.openjdk.java.net/~ysuenaga/JDK-8185796/webrev.01/

This webrev has been ported print_lock_info() to JavaVFrame.java,
and I've added new testcase for `jhsdb jstack` and jstack command on
`jhsdb clhsdb`.


Yasumasa


On 2017/08/24 18:01, Jini George wrote:

Apologize for the late reply, Yasumasa.


I think so, but I guess it is difficult.
For example, test for CLHSDB command is provided as
test/serviceability/sa/TestPrintMdo.java .
But target process seems to be fixed to "LingeredApp".
Can we change it to another program which generates lock
contention?


You can take a look at any of the
hotspot/test/serviceability/sa/LingeredAppWith*.java files for
this. The target process does not have to be be fixed to
LingeredApp -- in these LingeredAppWith* cases, the targets are
test-specific variations built on top of LingeredApp for ease of
implementation.

Thanks,
Jini.